Bolt for automatic weapon



Aug. l0, 1965 R. c. HENlsA 3,199,407

BOLT FOR AUTOMATIC WEAPON Filed may 22, 1964 34 36 92 3H 2a 33 2 l 375/27 9 /9 /4/: x a 2/ f6 M y /6 y LW26 2425 (/o 1&1

I NVEN TOR. ,1P/:Yuma C Hav/SH United States Patent O 3,199,407 BOLT FOR AUTOMATIC WEAPON Raymond C. Henisa, New York, N.Y. (RR. 3, Columbia City, Ind.) Filed May 22, 1964, Ser. No. 370,324 4 Claims. (Cl. 89-187) This invention relates generally to the field of firearms, and more specifically to a novel bolt mechanism for high chamber pressure automatic weapons.

The accuracy and performance of automatic rifles and similar weapons depends largely on the distribution of forces which take place upon ignition of the charge within the chamber. These forces must be restrained adequately to ensure accurate expulsion of the bullet, and at the same time must be utilized to re-load the firing mechanism, reject the spent cartridge and insert the subsequent round for firing. My invention is directed towards the provision of a bolt mechanism which is particularly suited for high chamber pressure operation by providing a positive locking of the bolt during the initial stages of tiring a round of ammunition.

It is therefore a primary object of this invention to provide a novel bolt construction for automatic weapons which is simple in design, effective and reliable in operation, and may be manufactured by economical high production techniques.

It is a further object of this invention to provide a bolt for an automatic weapon which is capable of operation with eXtreme rapidity, and wherein the several mechanical functions take place with a minimum of wear.

A full understanding of the details of this invention, together with further advantages, will become apparent by reference to the following detailed description of a preferred embodiment thereof, taken in conjunction with the attached drawings wherein:

FIG. 1 is a cross sectional fragmentary view of a receiver and chamber showing the bolt of my invention in the locked position during the initial stage of tiring.

FIG. 2 is a fragmentary cross sectional view showing the bolt at an instant before firing takes place.

Similar reference characters indicate corresponding parts throughout the several views in the drawings.

Referring now to the drawings in detail, the numeral 5 represents a receiver body having a cartridge chamber 6 formed towards one end of the body, and a cylindrical bolt housing 7 extending concentrically and longitudinally of the body and having a greater diameter than that of the chamber 6 to which it is also concentrically disposed.

The bolt consists of an outer cylinder 8 which terminates towards the chamber end of the receiver body with a conical rib 9 which is designed to pick up a round of ammunition from the magazine and guide the same into the chamber 6. The inner end 10 of the bolt is adapted to engage in a shaped recess 11 formed in the receiver body at the junction between the cartridge chamber 6 and the bolt housing 7. The other end 12 of the cylinder 8 is threaded at 13 to removably receive a closure cap 14 threaded thereon. A number of longitudinal slots 1S are formed radially through the outer cylinder in a symmetrically spaced manner therearound and inwardly spaced from the conical rib portion 9. These slots are adapted to align with similar slots 16 formed radially in the receiver body. The slots and 16 register with each other when the bolt is disposed in its innermost position with the end 10 engaging in the recess 1l.

The bolt has a concentric inner wall 17 and forms a conical end ring 18 extending inwardly to form part of the rib 9 and restrict the chamber end of the bolt. A floating bolt end 19 has a flat circular face 20 for abutment with the end of a cartridge. The bolt end flares outwardly and rearwardly to form a conical stop 2l for engaging with the end ring 18 of the rib 9. Extending rearwardly the floating bolt end forms a conical wedge 22 and terminates with an inner circular face 23 disposed parallel and concentrically with the flat face 20.

Flat locking lugs 24 have parallel side edges 25 and slideably locate in each of the longitudinal slots 15 of the cylinder 8 and are further adapted to be displaced radially and engage in the slots 16 formed in the receiver body. Small convex leaf springs 26 are disposed in the slots 16 so as to constantly urge the locking lugs away from engagement with the slots 16. The locking lugs terminate with edges 27 which locate outwardly of the centre of the cylinder 8 so as to permit a firing pin striker 28 to pass freely therebetween and also provide clearance for a re-set spring 29 which is mounted freely around the firing pin striker. Concave arcuate guide surfaces 30 are formed between the side edges of the lugs and the inwardly terminating edges 27 so as to functionally receive the conical wedge 22 of the floating bolt end 19 upon rearward movement thereof, and thereby force the locking lugs in an outward radial direction for locking engagement within the slots 16. Similar tapered surfaces 31 are formed between the remaining side edges of the locking lugs and the adjoining terminating edges 27. A ring pin 32 having a terminating tang 33 disposed outwardly of the bolt extends through a concentric opening 34 in the cap to terminate with the striker 28 which is slideably received in a bore 35 formed centrally through the floating bolt end 19. The firing pin stop 36 is secured about the firing pin to restrain rearward movement thereof against the inner surface of the closure cap 14. A firing pin wedge 37 is secured to the pin intermediate the ends thereof and has a forwardly directed spherical surface 38 for wedging engagement relative to the tapered surfaces 31 formed on the inner side of the locking lugs. The re-set spring 29 is mounted on the tiring pin and engages under compression between the spherical surface 38 and the flat face 23 of the bolt end so as to retract the firing pin and at the same time urge the floating bolt end 19 against the conical end ring 18 of the inner wall 17. A bushing 39 of cylindrical shape is received within the cylinder 8 and provides an end stop 40 to prevent the locking lugs from becoming dislocated from the slots 15 during operation.

In operation, the bolt moves forward after being released by the trigger, and during its passage through the housing 7 takes a round from the magazine and positions the same in the chamber 6. The trigger hammer strikes the firing pin tang 33 driving the same forwardly such that the firing pin wedge 37 engages the tapered surfaces 31 of the locking lugs and thereby forcing the lugs radially against the springs 26 into the slots 16. Forward movement of the pin continues until the striker protrudes beyond the flat face 20 to fire the round positioned in the chamber 6. The bolt is partially locked at this time with the firing pin wedge 37 engaging the locking lugs. The gas formed on firing forces the cartridge rearwardly against the flat face 20 of the bolt end 19 and causes the same to move rearwardly such that the wedge portion 22 engages the arcuate guide surfaces so as to fully lock the lugs 24 in the slots 16. The calibrated re-set spring 29 now operates against the wedge 37 to move the firing pin 32 rearwardly until the stop 36 engages the inner wall of the closure cap 14. As the chamber pressures decrease as the bullet leaves the barrel, the calibrated spring 29 urges the bolt end 19 forwardly until the conical stop 21 engages the end ring 18, thus providing clearance to permit the locking lugs to be ejected from the slots 16 and permit the bolt to move rearwardly against the bolt returning spring, not shown, so that the spent cartridge may be ejected and a fresh round may be brought into the chamber when the bolt again returns under automatic operation. It will be clear that this bolt may be readily disassembled for cleaning purposes when necessary.

Having described the invention with considerable particularity, it should be understood that various modifications may be made to the detail thereof, without departing from the scope or spirit of the invention, as defined in the appended claims.

I claim:

1. A bolt for an automatic Weapon having a receiver and cartridge chamber formed at one end, and comprising, an outer cylinder having a concentric inner wall, a conical rib extending inwardly adjacent one end of the cylinder, a floating bolt end received in the cylinder and engaging the inner side of the rib, iiat locking lugs extending radially through slots formed in the cylinder and adapted for radial movement into further slots formed in the receiver to lock the bolt in a closed firing position, a cap closing the other end of the cylinder, a firing pin extending concentrically through the cap and cylinder and through the oating bolt end, and spring and wedge means urging said lugs in and out of engagement with said further slots in response to longitudinal movement of the ring pin and said floating bolt end.

2. A bolt for an automatic weapon according to claim 1, wherein said spring and wedge means comprises, a conical wedge formed on the inner end of the iloating bolt end for engaging the lugs and urging radial movenient thereof in response to rearward movement of the bolt end, a firing pin wedge mounted on the ring pin and engaging said lugs to urge radial outward movement in response to forward movement of the ring pin, and a spring disposed between the ring pin wedge and the conical wedge for releasing engagement of said wedges from the lugs to permit retraction thereof out of said further slots.

3. A bolt for an automatic weapon according to claim K2, wherein arcuate springs are disposed within said further 1slots and wherein a bushing is received within the cylinder to provide a removable end stop preventing displacement of the lugs from the first slots.

4. A bolt for an automatic weapon having a receiver with a cylindrical bolt chamber, and comprising, a cylindrical body for moving longitudinally within the chamber, a conical rib forming an annular stop at one end of the body, a floating bolt end engaging inwardly against the stop, locking lugs disposed in radial slots through the body and selectively projecting into further slots formed in the chamber, said lugs extending into the body, a cap closing the other end of the body, a tiring pin extending concentrically through the cap and the body to selectively extend through a bore formed in the bolt end, a conical wedge formed on the bolt end to urge said lugs radially outwardly into the further slots in response to inward movement of the bolt end, a firing pin wedge secured on the tiring pin intermediate its ends for urging said lugs radially outwardly into the further slots in response to movement of the firing pin, and springs mounted in the further slots to urge the lugs radially outwardly from engagement therewith.

No references cited.

BENJAMIN A. BORCHELT, Primary Examiner. 

1. A BOLT FOR AN AUTOMATIC WEAPON HAVING A RECEIVER AND CARTRIDGE CHAMBER FORMED AT ONE END, AND COMPRISING, AN OUTER CYLINDER HAVING A CONCENTRIC INNER WALL, A CONICAL RIB EXTENDING INWARDLY ADJACENT ONE END OF THE CYLINDER, A FLOATING BOLT END RECEIVED IN THE CYLINDER AND ENGAGING THE INNER SIDE OF THE RIB, FLAT LOCKING LUGS EXTENDING RADIALLY THROUGH SLOTS FORMED IN THE CYLINDER AND ADAPTED FOR RADIAL MOVEMENT INTO FURTHER SLOTS FORMED IN THE RECEIVER TO LOCK THE BOLT IN A CLOSED FIRING POSITION, A CAP CLOSING THE OTHER END OF THE CYLINDER, A FIRING PIN EXTENDING CONCENTRICALLY THROUGH THE CAP AND CYLINDER AND THROUGH THE FLOATING BOLT END, AND SPRING AND WEDGE MEANS URGING SAID LUGS IN AND OUT OF ENGAGEMENT WITH SAID FURTHER SLOTS IN RESPONSE TO LONGITUDINAL MOVEMENT OF THE FIRING PIN AND SAID FLOATING BOLT MEANS. 